Incoloy 825
Ken-tron draws Incoloy A-286, Incoloy 800, Incoloy 825, Incoloy 330, and other high-temperature and corrosion-resistant alloys for customers in the aerospace, power generation, mechanical-fastener, heating, chemical-processing, and other industries. The most commonly ordered grade is Incoloy 825 (UNS N08825), a nickel-iron-chromium-molybdenum-copper alloy engineered specifically for resistance to reducing and oxidizing acids.
Incoloy 825 combines nickel and molybdenum for resistance to reducing environments, chromium for resistance to oxidizing conditions, and a molybdenum-copper addition that gives the alloy particularly good resistance to sulfuric and phosphoric acid attack — environments where standard austenitic stainless steel can suffer accelerated corrosion.
Chemical Composition
| Element | Incoloy 825 (wt%) |
|---|---|
| Nickel (Ni) | 38.0 – 46.0 |
| Chromium (Cr) | 19.5 – 23.5 |
| Iron (Fe) | 22.0 min |
| Molybdenum (Mo) | 2.5 – 3.5 |
| Copper (Cu) | 1.5 – 3.0 |
| Titanium (Ti) | 0.6 – 1.2 |
| Manganese (Mn) | 1.0 max |
| Silicon (Si) | 0.5 max |
| Carbon (C) | 0.05 max |
| Aluminum (Al) | 0.2 max |
| Sulfur (S) | 0.03 max |
Source: ASTM B425-19, Table 1 (UNS N08825 column). Iron content is determined arithmetically by difference.
Mechanical Properties
ASTM B425 Rod/Bar Baseline (Annealed)
| Condition | Tensile Strength, min (ksi) | Yield Strength (0.2% offset), min (ksi) | Elongation, min % |
|---|---|---|---|
| Annealed, hot-finished/cold-drawn | 85 | 35 | 30 |
Source: ASTM B425-19, Table 2. Not applicable to diameters or cross-sections under 3/32 in.
Ken-tron Typical Drawn-Wire Tensile Strength
| Condition | Tensile Strength (ksi) |
|---|---|
| Annealed | 87 – 116 |
| Spring Temper | 116 – 160 |
Source: Ken-tron typical values for cold-drawn fine wire, which develops higher strength than the rod/bar minimums in ASTM B425 due to greater cumulative cold reduction. Confirm target temper and diameter with Ken-tron engineering for a specific application.
Temperature Coefficient of Thermal Expansion
| Temperature Range | Mean CTE (µm/m/°C) |
|---|---|
| 21 – 93°C | 14 |
Physical Properties
| Property | Value |
|---|---|
| Density | 0.294 lb/in³ |
| Melting Point | ≈2,552°F |
| Magnetic Permeability | Essentially non-magnetic (austenitic matrix) |
Corrosion Resistance
- Good resistance to sulfuric and phosphoric acid environments across a range of concentrations and temperatures
- Resistant to chloride-ion stress-corrosion cracking and pitting, an advantage over standard austenitic stainless grades
- Titanium addition stabilizes the alloy against sensitization during welding or heat exposure
- Nickel-molybdenum content provides resistance to reducing acids, while the chromium content resists oxidizing conditions
Applicable Standards & Specifications
| Standard | Scope | Grade |
|---|---|---|
| ASTM B425-19 | Nickel-iron-chromium-molybdenum-copper alloy rod and bar — chemistry and mechanical reference | UNS N08825 |
| ASTM B424 | Ni-Fe-Cr-Mo-Cu alloy plate, sheet, and strip | Same alloy family |
| ASTM B880 | General requirements for chemical check-analysis limits, nickel alloys | All nickel alloy product |
Industries & Applications
| Industry | Typical Applications |
|---|---|
| Chemical Processing | Sulfuric and phosphoric acid handling equipment |
| Aerospace & Power Generation | Corrosion-resistant structural and fastener applications |
| Marine & Oil/Gas | Components exposed to chloride-rich, acidic environments |
| Heating & Fasteners | Mechanical fasteners, heating elements |
Incoloy 825 vs. 316L Stainless Steel
Both alloys are corrosion-resistant, but Incoloy 825’s higher nickel and molybdenum content extend its resistance into more aggressive acid environments than 316/316L can reliably handle:
| Property | Incoloy 825 | 316L Stainless Steel |
|---|---|---|
| Nickel Content | 38.0 – 46.0% | 10.0 – 14.0% |
| Molybdenum Content | 2.5 – 3.5% | 2.0 – 3.0% |
| Sulfuric/Phosphoric Acid Resistance | Good across a wide concentration/temperature range | Limited — susceptible to accelerated attack in strong acid |
| Typical Use | Chemical processing, acid handling | General corrosion resistance, medical, food-grade |
Ken-tron Wire Drawing Capability
The Ken-tron Wire Division specializes in small-diameter, close-tolerance wire made to customer specifications. Our manufacturing process for Incoloy 825 wire includes:
- Incoming material verification — mill certifications reviewed, chemistry confirmed against applicable standard
- Controlled cold reduction — percentage reduction between anneals managed to achieve target temper and dimensional tolerance
- In-process and final annealing — controlled-atmosphere annealing to preserve corrosion resistance and prevent sensitization
- Dimensional inspection — diameter measured using calibrated gauges; tolerance held to customer specification
- Surface inspection — wire examined for seams, laps, or inclusions affecting corrosion performance
- Certification and documentation — mill certs and material traceability furnished with each shipment
Ken-tron manufactures to your custom specifications. For additional inquiries, please request a quote or contact us.